Field of the Invention
The present invention relates to a cooling system of an engine dividing vertically a coolant jacket corresponding to a cylinder liner of a cylinder block and controlling a flow of a coolant circulating the coolant jacket to improve an entire cooling efficiency and to reduce an abnormal combustion of a combustion chamber.
Description of Related Art
Engines produce torque by burning a fuel to create energy, and discharge surplus thermal energy. Particularly, a coolant absorbs thermal energy as it circulates through an engine, a heater, and a radiator, and releases the thermal energy.
Oil becomes highly viscous at low engine coolant temperatures. With thick oil, friction and fuel consumption increase, and exhaust gas temperatures rise gradually, lengthening the time taken for catalyst activation and causing deterioration in exhaust gas quality. Moreover, it takes a long time to get a heater to function normally, so passengers and a driver will feel cold at low temperatures.
When the engine coolant temperature is excessively high, knocking may occur. If ignition timing is adjusted to suppress knocking, the engine performance may be degraded. In addition, excessive lubricant temperatures may result in poor lubrication.
However, one coolant control valve is used in specific regions of an engine, and is a valve that controls a number of cooling elements, like keeping the coolant at high temperatures and other regions at low temperatures.
Among the several cooling elements, a cylinder block and a cylinder head are important, and a technique of separately cooling the cylinder block and the cylinder head has been researched.
On the other hand, since the top part of the cylinder block is adjacent to the combustion chamber, the temperature thereof is high, since the bottom part of the cylinder block is far away from combustion chamber, the temperature thereof is low, in this case, because the coolant is controlled by one coolant jacket, it is difficult to respectively control the top part and the bottom part to be optimized.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.